Introduction; Intended Use; General Information - JUMO NESOS Manual De Servicio

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Introduction

2.1

Intended use

Float switches or level switches are used to measure the level of liquid media in containers or tanks. Lev-
el transmitters with floats provide a virtually continuous level measurement of liquid media in containers
or tanks. The respective application limits result from the technical data and specified materials with re-
gard to chemical resistance.
The liquids must not contain any heavy pollutants or coarse components that damage the floats or pre-
vent them from being able to move (e.g. paints, dispersions, abrasive media, magnetic suspended sol-
ids).
The technical features in this operating manual must be complied with. Improper handling or operation
of the product outside of the technical features will invalidate the warranty. Claims of any kind due to im-
proper use are null and void. For further issues, the general terms and conditions apply.
When using the product in explosion-proof areas, the respective type examination certificate
(chapter 9.2 "Examination certificate", Page 21) for intrinsic safety or flameproof enclosure must be ob-
served.
When using the product in shipbuilding, the certificate (chapter 9.3 "Certificate for shipbuilding",
Page 21) must be observed.
WARNING!
The Ex approval becomes null and void if the device is used contrary to its intended use or if the safety
requirements in this operating manual are not complied with.
WARNING!
Ensure adequate chemical resistance of the product to the liquids used. The wetted parts of the products
can be found in the data sheet of the respective product group number under „mechanical features".
2.2

General information

The limit and level measurement takes place according to the Archimedean principle for liquids. The float
moves along the guide tube as the level rises or falls.
The magnet in the float actuates the reed contact(s) installed in the guide tube with its magnetic field.
The switching status of the reed contact can be evaluated and processed through downstream electron-
ics. The electrical connection, process connection, guide tube length, float, as well as the number, posi-
tion, and function of the contacts may vary depending on the ordered variant.
The float switch is used to switch small loads such as lamps, horns, PLC inputs, motor controls, pumps
or valves.
With the level transmitter, the levels of tanks and containers are transferred with a standard signal.
When connecting to intrinsically safe electrical circuits, the intrinsically safe version of the product (Ex i)
fulfils the requirements for explosion group II of categories 1/2 G and 1/2 D, as well as 2 G und 2 D.
It is therefore suitable for use in the potentially explosive area of zone 0, 1 and 2 for gas (G) and zone
21 and 22 for dust (D). A certified, intrinsically safe isolation amplifier or supply isolator in Ex ia must be
used.
When connecting to electrical circuits that are not intrinsically safe, the version of the product with flame-
proof enclosure (Ex d) fulfils the requirements for explosion group II of category 1/2 G and 2 D.
It is therefore suitable for use in the potentially explosive area of zone 0, 1 and 2 for gas (G) and zone
21 and 22 for dust (D).
The product does not fall under the Pressure Equipment Directive 2014/68/EU, since there is no pres-
surized housing (see separate certificate TÜV SÜD).
The following figure shows a schematic example of the structure of a float switch.
2 Introduction
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